In an engine for a portable working machine such as a brush cutter, a chain saw, a hedge trimmer, and a blower, an air cleaner is detachably equipped on the outer side of an intake port of a carburetor to prevent dust etc. from entering the engine through the intake port of the carburetor (see Japanese Patent Application Publication No. H9-72220).
The air cleaner is typically provided with a lid member (an air cleaner lid) configured to cover a front face of the intake port of the carburetor to form an air inlet path toward the intake port of the carburetor, and has such a structure that a filter is disposed between the lid member and the intake port of the carburetor.